Gender and racial/ethnic background predict weight loss after Roux-en-Y gastric bypass independent of health and lifestyle behaviors.

Our study investigated how demographic, health, and behavioral factors interacted to affect weight outcomes in bariatric patients. Roux-en-Y gastric bypass (RYGB) patients who were non-Hispanic black, Hispanic, or non-Hispanic white race/ethnicity, had no revisions to their RYGB during 2004-2009, and had at least 1 year of follow-up data for body weight after surgery (n = 860) were surveyed by phone about their health and behaviors. The main outcomes of interest were percent excess weight loss and percent of initial weight lost. Participants were 47 ± 11 years old, 54 % non-Hispanic white, 25 % Hispanic, and 21 % non-Hispanic black, 82 % female, 60 % married, 82 % had some college education, and 47 % had an annual income between $35,000 and $80,000. At the time of surgery, patients had lost 50 ± 29 % of their excess weight and had achieved 24 ± 15 % initial weight lost after an average of 54 months of follow-up. After accounting for weight at the time of surgery, demographics, and self-reported health and behavior, non-Hispanic black men had significantly greater weight loss compared to non-Hispanic white men (p < .05). There were no differences between racial/ethnic groups of women in weight outcomes. Percent excess weight loss was related to greater diet soda intake, and percent initial weight lost was related to greater water intake. Independent of health status and lifestyle behaviors, age, and weight at the time of surgery, race/ethnicity, gender, and diet soda and water intake were the strongest predictors of weight outcomes after RYGB surgery.